The road has been shut for accident investigation work both ways from the B2028 Turners Hill Road (The Dukes Head pub) to the B2037 (Shell garage), the AA said. It has been closed since 10pm last night.
The fire service said they attended a collision involving a car on the A264 at Snow Hill, Crawley Down.
A spokesman added: “One appliance from Crawley and one from Turners Hill, plus the rescue tender from Crawley, attended.
“Thermal imaging camera used and firefighters assisted SECAmb.”
Sussex Police have been approached for comment.